Sibling differences and parents' differential treatment of siblings: A multilevel meta-analysis.

The current study used meta-analysis to ask whether age differences, sex differences, and family size are linked to differences in parental treatment, as well as whether effect-sizes were moderated by the way parental differential treatment (PDT) was measured, who reported on the PDT, and the domain of PDT. Between August 2015 and November 2020, PsycINFO, Google Scholar, and PubMed Central were searched for articles relating to parental differential treatment; additionally, 13 sibling relationship scholars were contacted to collect unpublished analyses or unused data. Multilevel data came from 13,628 unique participants across 1,388 effect sizes nested within 66 sources (articles/raw data sets), nested within 23 unique samples (74% from North America; 26% from Western Europe). Multilevel meta-analysis conducted in R with the metafor package showed greater differences in parental treatment when siblings were further apart in age or a different sex. The main effects for age spacing, however, were moderated by several factors, particularly the domain of parenting. Specifically, age spacing was linked only to PDT based on control or autonomy granting, meaning when siblings were further apart in age, parents granted more autonomy to one sibling over another. Results were limited, however, by limited sample sizes at the sample level. Overall, findings suggest that parents may, in part, treat siblings differently because they are different to begin with. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

The family stress model and parents' differential treatment of siblings: A multilevel meta-analysis.

The family stress model (FSM) suggests that stress, particularly economic stress, hinders effective parenting. Expanding on the FSM, the present study examined not only the economic stress but also the general stress and several contexts that may promote stress-namely, physical health, mental health, socioeconomic status, employment status, and marital status. The present study also expanded the FSM to examine parenting of sibling groups. Ineffective parenting of sibling groups was conceptualized as greater parental differential treatment (PDT). A number of moderating variables were also considered. Multilevel meta-analysis models were used to test hypotheses. Across models, data came from 6,003 effect sizes, nested within 59 sources, nested within 16 unique samples (all coming from 8 published studies and 11 raw data sets). Results showed main effects for only parents' general stress and parents' mental health. More stress and poorer mental health were linked with greater amounts of PDT. Additionally, poorer physical health was linked to greater PDT but only when PDT involved positive parent-child interactions. As a whole, findings suggested that actual feelings of stress and psychological distress may show stronger links with PDT than contexts that merely have the potential to cause stress. Caution is warranted, however, as effect sizes were generally small and some models were based on predominantly Caucasian samples. Future research on the FSM and PDT should focus on actual experiences of stress and further consider the moderating role of domains of parenting. (PsycInfo Database Record (c) 2022 APA, all rights reserved).